Tuesday, May 4, 2010

Children with hearing loss in one ear fall behind in language skills

By the time they reach school age, one in 20 children have hearing loss in one ear. This one impediment can raise significant hurdles for these children, because the loss of hearing in one ear hurts their ability to comprehend and use language.

"For many years, paediatricians and educators thought that as long as children have one normal hearing ear, their speech and language would develop normally," says Judith E. C. Lieu, MD, a Washington University ear, nose and throat specialist at St. Louis Children's Hospital.

"But then a few studies began suggesting these children might have problems in school. Now our study has shown that on average, children with hearing loss in one ear have poorer oral language scores than children with hearing in both ears," Lieu says.

Hearing loss in one ear can stem from congenital abnormalities in the ear, head trauma or infections such as meningitis. Children with hearing loss in one ear may go undetected because they can appear to have normal hearing. Their difficulty hearing may be mistaken simply for lack of attention or selective hearing, says Lieu, assistant professor of otolaryngology.

Even children with recognised 'one-side hearing loss' often aren't fitted with hearing aids and often don't receive accommodations for their impediment.

The researchers studied 74 six- to 12-year-old children with hearing loss in one ear. Each was matched with a sibling with normal hearing so that the researchers could minimise the possible effects of environmental and genetic factors on the children's language skills. The children were tested with the Oral and Written Language Scales (OWLS), a widely used tool to assess language comprehension and expression.

An average OWLS score is 100, and hearing loss in one ear caused, on average, a 10-point drop in scores. The oral composite score, which reflects both children's ability to understand what is said to them and their ability to respond or express themselves, averaged 90 in children with hearing loss in one ear.

Lieu says that the study demonstrated the strongest effect from hearing loss in one ear in children who are living below the poverty level or with mothers who have little education. Poverty levels and maternal education levels are well-established influences on language skills, and hearing loss in one ear may increase that effect.

"This study should raise awareness that if children with hearing loss in one ear are having difficulties in speech or reading in school, their hearing may be part of the problem," Lieu says. "Parents, educators and paediatricians shouldn't assume that having hearing in one ear means children won't need additional assistance."

The study does not address which possible solutions will be most effective for overcoming the decrease in language skills seen in the children with hearing loss in one ear, but Lieu suggests that studies could be done to see if hearing aids or amplification systems in the classroom will help.

In addition, having an educational audiologist as part of an individualised educational plan also might be beneficial.

"The effect of hearing loss in one ear may be subtle," Lieu says. "These children may shun large group situations because the noise overwhelms them, and they have a hard time understanding speech. They could have difficulties playing team sports because they can't localise sound as well as others and therefore, can't tell who is calling to them or from which direction.

"For them, listening takes a lot more work, and they may have to put in extra effort," Lieu says. "We don't know yet if the hearing loss ultimately affects their overall educational achievement and eventually, even which occupations they choose."

Clearly there is still much to discover with this study but it does re-enforce the need to check the hearing of children who are having learning difficulties or are not socialising as well as they might.

As an adult who has been deaf in one ear all his life and dyslexic, I recently decided to investigate the two problems. I came to a conclusion that if you're deaf in one ear you will by definition have Auditory Processing Disorder. The two most obvious types of auditory processing disorder which are experienced by people with single sided deafness are the ability to tell direction which a sound is coming from and the ability to carry out a conversation in a noisy environment.Auditory Processing Disorder is recognized as one of the major causes of dyslexia. Some children can acquire auditory processing disorder as a result of experiencing otitis media with effusion (glue ear, sticky ear, grommets) and other severe ear conditions.